To evaluate the charge transport properties of as-grown high resistivity CdZnTe crystals doped with In/Al, the α particle spectroscopic response was measured using an un-collimated 241Am (5.48 MeV) radioactive sour...To evaluate the charge transport properties of as-grown high resistivity CdZnTe crystals doped with In/Al, the α particle spectroscopic response was measured using an un-collimated 241Am (5.48 MeV) radioactive source at room temperature. The electron mobility lifetime products (μτ)e of the CdZnTe crystals were predicted by fitting plots of photo-peak position versus electrical field strength using the single carrier Hecht equation. A TOF technique was employed to evaluate the electron mobility for CdZnTe crystals. The mobility was obtained by fitting the electron drift velocities as a function of the electrical field strengths, where the drift velocities were achieved by analyzing the rise-time distributions of the voltage pulses formed by a preamplifier. A fabricated CdZnTe planar detector based on a low In concentration doped CdZnTe crystal with (μτ)e = 2.3 × 10?3 cm2/V and μe =1000 cm2/(V·s), respectively, exhibits an excellent γ-ray spectral resolution of 6.4% (FWHM = 3.8 keV) for an un-collimated 241Am @ 59.54 keV isotope.展开更多
As the key component of electrochemical energy storage devices, an electrode with superior ions transport pores is the important premise for high electrochemical performance. In this paper, we developed a unique solut...As the key component of electrochemical energy storage devices, an electrode with superior ions transport pores is the important premise for high electrochemical performance. In this paper, we developed a unique solution process to prepare freestanding TiO_2/graphene hydrogel electrode with tunable density and porous structures. By incorporating room temperature ionic liquids(RTILs), even upon drying, the non-volatile RTILs that remained in the gel film would preserve the efficient ion transport channels and prevent the electrode from closely stacking, to develop dense yet porous structures. As a result, the dense TiO_2/graphene gel film as an electrode for lithium ion battery displayed a good gravimetric electrochemical performance and more importantly a high volumetric performance.展开更多
Many cities,countries and transport operators around the world are striving to design intelligent transport systems.These systems capture the value of multisource and multiform data related to the functionality and us...Many cities,countries and transport operators around the world are striving to design intelligent transport systems.These systems capture the value of multisource and multiform data related to the functionality and use of transportation infrastructure to better support human mobility,interests,economic activity and lifestyles.They aim to provide services that can enable transportation customers and managers to be better informed and make safer and more efficient use of infrastructure.In developing principles,guidelines,methods and tools to enable synergistic work between humans and computer-generated information,the science of visual analytics continues to expand our understanding of data through effective and interactive visual interfaces.In this paper,we describe an application of visual analytics related to the study of movement and transportation systems.This application documents the use of rapid,2D and 3D web visualisation and data analytics libraries and explores their potential added value to the analysis of big public transport performance data.A novel approach to displaying such data through a generalisable framework visualisation system is demonstrated.This framework recalls over a year’sworth of public transport performance data at a highly granular level in a fast,interactive browser-based environment.Greater Sydney,Australia forms a case study to highlight potential uses of the visualisation of such large,passively-collected data sets as an applied research scenario.In this paper,we argue that such highly visual systems can add data-driven rigour to service planning and longer-term transport decision-making.Furthermore,they enable the sharing of quality of service statistics with various stakeholders and citizens and can showcase improvements in services before and after policy decisions.The paper concludes by making recommendations on the value of this approach in embedding these or similar web-based systems in transport planning practice,performance management,optimisation and understanding of customer experience.展开更多
Using lower-cost lasers, 30% savings are possible for 10-Gb/s uncompensated metro transmission over NZDF, compared to G.652 fiber. We present WDM transmission results for a mixed plant of NZDF rings interconnected to ...Using lower-cost lasers, 30% savings are possible for 10-Gb/s uncompensated metro transmission over NZDF, compared to G.652 fiber. We present WDM transmission results for a mixed plant of NZDF rings interconnected to G.652.C-fiber access laterals.展开更多
Two-dimensional(2D)materials hold great potential for the development of next-generation integrated circuits(ICs)at the atomic limit.However,it is still very challenging to build high performance devices.One of the ma...Two-dimensional(2D)materials hold great potential for the development of next-generation integrated circuits(ICs)at the atomic limit.However,it is still very challenging to build high performance devices.One of the main factors that limit the incorporation of 2D materials into IC technology is their relatively low carrier mobility.Thus,the engineering strategies that focus on optimizing performance continue to emerge.Herein,using a spatiotemporal resolved pump-probe setup,the carrier transport performance and relaxation process of few-layer and bulk MoSe_(2) under pressure were investigated nondestructively and simultaneously.Our results show that pressure can tune the transport performance effectively.In particular,under pressure regulation,the carrier mobility of the bulk MoSe_(2) increases by~4 times;meanwhile,the carrier lifetimes of the samples become shorter.Although the processes almost return to their initial state after the pressure release,it is still surprising to see that the carrier mobilities of fewlayer and bulk MoSe2 are still~1.5 and 2 times enhanced,and carrier lifetimes are still shorter than the initial state.Combined with the Raman spectra under pressure,we consider that it is caused by the enhanced layer coupling and lattice compression.The combination of enhanced mobility and shortened lifetime in MoSe_(2) under pressure holds great potential for optoelectronic applications under the deep ocean and deep earth.展开更多
文摘To evaluate the charge transport properties of as-grown high resistivity CdZnTe crystals doped with In/Al, the α particle spectroscopic response was measured using an un-collimated 241Am (5.48 MeV) radioactive source at room temperature. The electron mobility lifetime products (μτ)e of the CdZnTe crystals were predicted by fitting plots of photo-peak position versus electrical field strength using the single carrier Hecht equation. A TOF technique was employed to evaluate the electron mobility for CdZnTe crystals. The mobility was obtained by fitting the electron drift velocities as a function of the electrical field strengths, where the drift velocities were achieved by analyzing the rise-time distributions of the voltage pulses formed by a preamplifier. A fabricated CdZnTe planar detector based on a low In concentration doped CdZnTe crystal with (μτ)e = 2.3 × 10?3 cm2/V and μe =1000 cm2/(V·s), respectively, exhibits an excellent γ-ray spectral resolution of 6.4% (FWHM = 3.8 keV) for an un-collimated 241Am @ 59.54 keV isotope.
基金supported by grants from the National Natural Science Foundation of China(21303251)Innovation Program of Shanghai Municipal Education Commission(16SG17)the Shenzhen Science and Technology Foundation(JCYJ201419122040621)
文摘As the key component of electrochemical energy storage devices, an electrode with superior ions transport pores is the important premise for high electrochemical performance. In this paper, we developed a unique solution process to prepare freestanding TiO_2/graphene hydrogel electrode with tunable density and porous structures. By incorporating room temperature ionic liquids(RTILs), even upon drying, the non-volatile RTILs that remained in the gel film would preserve the efficient ion transport channels and prevent the electrode from closely stacking, to develop dense yet porous structures. As a result, the dense TiO_2/graphene gel film as an electrode for lithium ion battery displayed a good gravimetric electrochemical performance and more importantly a high volumetric performance.
文摘Many cities,countries and transport operators around the world are striving to design intelligent transport systems.These systems capture the value of multisource and multiform data related to the functionality and use of transportation infrastructure to better support human mobility,interests,economic activity and lifestyles.They aim to provide services that can enable transportation customers and managers to be better informed and make safer and more efficient use of infrastructure.In developing principles,guidelines,methods and tools to enable synergistic work between humans and computer-generated information,the science of visual analytics continues to expand our understanding of data through effective and interactive visual interfaces.In this paper,we describe an application of visual analytics related to the study of movement and transportation systems.This application documents the use of rapid,2D and 3D web visualisation and data analytics libraries and explores their potential added value to the analysis of big public transport performance data.A novel approach to displaying such data through a generalisable framework visualisation system is demonstrated.This framework recalls over a year’sworth of public transport performance data at a highly granular level in a fast,interactive browser-based environment.Greater Sydney,Australia forms a case study to highlight potential uses of the visualisation of such large,passively-collected data sets as an applied research scenario.In this paper,we argue that such highly visual systems can add data-driven rigour to service planning and longer-term transport decision-making.Furthermore,they enable the sharing of quality of service statistics with various stakeholders and citizens and can showcase improvements in services before and after policy decisions.The paper concludes by making recommendations on the value of this approach in embedding these or similar web-based systems in transport planning practice,performance management,optimisation and understanding of customer experience.
文摘Using lower-cost lasers, 30% savings are possible for 10-Gb/s uncompensated metro transmission over NZDF, compared to G.652 fiber. We present WDM transmission results for a mixed plant of NZDF rings interconnected to G.652.C-fiber access laterals.
基金supported by the Fundamental Research Funds for the Central Universities+2021RC203the National Natural Science Foundation of China(Nos.11974088,61875236,and 61975007)+2 种基金the Beijing Natural Science Foundation(Nos.Z190006 and 4222073)the National Key R&D Program of China(Nos.2021YFA1400300 and 2020YFA0711502)the Synergetic Extreme Condition User Facility(SECUF),Chinese Academy of Sciences,for the Diamond anvil cell.
文摘Two-dimensional(2D)materials hold great potential for the development of next-generation integrated circuits(ICs)at the atomic limit.However,it is still very challenging to build high performance devices.One of the main factors that limit the incorporation of 2D materials into IC technology is their relatively low carrier mobility.Thus,the engineering strategies that focus on optimizing performance continue to emerge.Herein,using a spatiotemporal resolved pump-probe setup,the carrier transport performance and relaxation process of few-layer and bulk MoSe_(2) under pressure were investigated nondestructively and simultaneously.Our results show that pressure can tune the transport performance effectively.In particular,under pressure regulation,the carrier mobility of the bulk MoSe_(2) increases by~4 times;meanwhile,the carrier lifetimes of the samples become shorter.Although the processes almost return to their initial state after the pressure release,it is still surprising to see that the carrier mobilities of fewlayer and bulk MoSe2 are still~1.5 and 2 times enhanced,and carrier lifetimes are still shorter than the initial state.Combined with the Raman spectra under pressure,we consider that it is caused by the enhanced layer coupling and lattice compression.The combination of enhanced mobility and shortened lifetime in MoSe_(2) under pressure holds great potential for optoelectronic applications under the deep ocean and deep earth.